Direct BPSK/QPSK demodulation by polarisation rotation

A novel method of demodulating BPSK and QPSK signals is presented. The system employs a traveling wave circularly polarized antenna with two ports, the annular sector radiating line (ANSERLIN) antenna. The antenna is setup to produce by superposition of two contra rotating circularly polarized signals linear polarization whose tilt angle is dependant on the PSK phase states. The polarization sensitivity of a simple dipole operating in concert with a standard detector diode was used to successfully produce unique amplitude levels corresponding the both BPSK and QPSK phase states. The technique described here forms the basis of a direct phase to amplitude conversion system viable as a simple means for obtaining direct BPSWQPSK demodulation based on magnitude detection only, hence the normal requirements for coherent carrier recovery electronics are removed.